Thought I start a thread where we can all share how 3D printing can be used to make various bits required for any wind sports. An entry level 3D printer now costs $200 AUD, a good quality one under $1000 and filament costs around $30/Kg so it is within reach of anyone. Many of the CAD programs to design your own stuff are free for hobbyists and there are plenty of Youtube tutorials showing how to use them.
So far most people using 3D prints seem to cover the prints in fibreglass or carbon to gain strength which is fine but there is an easier and cheaper way which just involves filling the pore space with something..typically epoxy but can be other materials.
To kick start the thread, video below of how I manufacture a 3D printed fin quickly for under $30 AUD. Since filming this video I've further reduced price to around $15 per fin but haven't had a chance to sail it yet. A commercial fin can cost $250 or more, so you can buy a printer and build a fins for the same cost. Originally this concept was just intended for rapid brief testing of concepts, it turns out the fins are reliable and long lasting. Many ideas to follow. Definitely more rewarding building and sailing your own stuff and heaps cheaper. Hope others will be inspired and share.
At this stage it seems we can play around with the degree of flex depending on what you fill the shell with. This one is filled with epoxy and has carbon rods.
Flex has done a wide array of variants you can see more here:
www.seabreeze.com.au/forums/Windsurfing/Gps/FangyFin-DIY-help--hints-and-show-us-ya-fin-page?page=23
and there are probably more floating about on other threads, I have just forgotten which ones.
Select to expand quoteMr Milk said..
Are the fins stiff?
You can control the stiffness of the fin by adjusting the infill density, the type of epoxy, the amount of carbon rods and additives like cotton flock or milled glass fibre. (Probably can use more exotic filaments to make stiffer but hasn't seemed necessary so I haven't tried yet even though I've bought the filaments) To answer your question:- Yes, you can make them as stiff (or as flexy) as you want. Photo below shows a 3D printed fin and a quality G10 fin (Tribal WS 31) both loaded at 18cm from the board with a 20Kg bag of salt. I couldn't measure any difference in deflection angle using Fusion 360. I have been playing around with all this and working on anther video. Trouble is both lack of wind for testing and me being slow at editing videos means I can make fins much faster than videos. 
Looks like I might have to get me a 3D printer.
My biggest problem is driving the CAD program. My head works much better on a physical object, not numbers on paper or shapes on a screen.
I also need to make a case for my screen-less head logger.
Select to expand quotedecrepit said..
Looks like I might have to get me a 3D printer.
My biggest problem is driving the CAD program. My head works much better on a physical object, not numbers on paper or shapes on a screen.
I also need to make a case for my screen-less head logger.
You'll have endless hours of "fun" trying to wrap your brain around the CAD programs. Of the three I used, I found only, the first one somewhat intuitive, but it was also very limiting. The other two were more powerful, but required watching lots of tutorials to understand their logic enough to make anything halfway complicated. But maybe it's easier for you, since you may not have so many notions about how things would/should be done...
Love your work Flex. Have you considered removing bubbles by either vacuum/pressure or ultrasonic vibration in the cooling bath?
Select to expand quote[b]boardsurfr said..[/b
You'll have endless hours of "fun" trying to wrap your brain around the CAD programs. Of the three I used, I found only, the first one somewhat intuitive, but it was also very limiting. The other two were more powerful, but required watching lots of tutorials to understand their logic enough to make anything halfway complicated. But maybe it's easier for you, since you may not have so many notions about how things would/should be done...
So I'll play with the software before I buy the hardware. I don't think it will be any easier for me!
Would be interesting to insert aluminum down the spine to stiffen and provide protection from grounding?
You could almost rivet sides onto a central spine then cover the heads with filler.
Select to expand quoteGasHazard said..
What range of materials can you print with?
Cobra are printing 3D irons and putters 
Select to expand quoteJetlag said..
Love your work Flex. Have you considered removing bubbles by either vacuum/pressure or ultrasonic vibration in the cooling bath?
yeah, I considered but after building about 15 fins this way so far, its really not needed. It would add lots of cost and complexity. Just not mixing epoxy too vigorously and not fully pushing the syringe plunger all the way does the trick to eliminate most air bubbles. Most of the seepage of epoxy comes out the seam (where the 3D print changes to the next layer). You can eliminate this by placing the seam inside the trailing edge PETG slot, then welding the PETG trailing edge in (dichloromethane) before filling the fin.
Select to expand quoteGrantmac said..
Would be interesting to insert aluminum down the spine to stiffen and provide protection from grounding?
You could almost rivet sides onto a central spine then cover the heads with filler.
lots of possibilities, early prototypes used a central stainless steel core but sort of been going the opposite way and making it simpler. Done well over 1000km on these fins now and a lot of dredging and impacts and not one fin has been damaged. Only damage is to the PETG trailing edge for the more wacky ideas where I extend the sheet below the print. The sheet seems to catch and then tear along the sheet/print interface. Been testing a cheaper fin (about $13 AUD) over the last two days in ballistic conditions and really thought it would break but only thing that broke was my fin cam trying to record the action. Gonna be spending quite some time today searching for the camera so can post some pics.
Select to expand quoteGasHazard said..
What range of materials can you print with?
So far I've mainly focused on PETG as cheap and easy (plus as mentioned recyclable for any mistakes) but you can print with a huge range of materials pretty much only limit is your wallet. The plan is to try PLA (corn based) and a natural filler for environmental reasons but so many other concepts to try haven't got around to that yet. I have a high end printer to be able to handle exotic filaments such as PC, PAHT-CF and PA6-CF which I also purchased but since the fins using simple PETG work just great haven't got around to trying them.
Great work Flex, this looks really interesting.
Perhaps you could recommend a few suitable printer models?
Forget printing in Stainless Steel unless your salary has 6 zeros in it....
Mine does $000000
Select to expand quotetbwonder said..
Great work Flex, this looks really interesting.
Perhaps you could recommend a few suitable printer models?
I have just gone through this process and badgered Flex relentlessly so I reckon I can give you a distilled version of printers that are good for the more common printing filaments.
Prusa Mk4 - very good quality, reliable machines and high customer service standard, one of the very few printers not made in China. Open source and large enthusiastic community.
Bambu Lab P1P - industry disrupter, from China. High quality/leading edge tech printers at approx 50% the price of landing a Prusa in Australia. Completely closed source on hardware and software and retailing. (Similar to the Apple's approach). Customer service reportedly very good. Higher end model Bambu Lab X1 for printing more exotics filaments etc.
Dozens of other companies in China producing varying levels of machines and disappointment, trading off against price. From what I could find out online (YouTubers reviews, forums), probably Creality K1 would be next on my list.
Select to expand quoteFlex2 said..GasHazard said..
What range of materials can you print with?
So far I've mainly focused on PETG as cheap and easy (plus as mentioned recyclable for any mistakes) but you can print with a huge range of materials pretty much only limit is your wallet. The plan is to try PLA (corn based) and a natural filler for environmental reasons but so many other concepts to try haven't got around to that yet. I have a high end printer to be able to handle exotic filaments such as PC, PAHT-CF and PA6-CF which I also purchased but since the fins using simple PETG work just great haven't got around to trying them.
Can't wait to see the fins you print in PLA. They will be morphing fins that change shape as soon as they get sunlight on them. There's a reason we don't print aircraft with PLA! PC or ASA are a lot more stable.
You may be able to print a fin for $30 in materials but the time and effort you put into it are better spent for most people. Buying a fin for $200 will seem reasonable once you factor in your time spent designing, building and refining the process.
The problem is finding off the shelf fins which can handle seriously heavy weed. There are some.
The next fun part is places like Albany can absolutely destroy a leading edge within 4 hours and @ $300 a pop you just grimace a lot when you see your nice fin munted.
As the largest fin we use in these areas are generally about 23cm, 3D printing gives a good idea on fin performance without big expense as a piece of G10 to suit is +$100 just for material let alone + the days worth of machining on a CNC Router then the cleanup after.
Flex's been using PET G successfully, PC would be a better option, but more expensive and can be a pain without a heated chamber Flex has a Bamboo labs printer which I think is ok , mine (Ender 6) struggles a bit with PC.
Select to expand quoteelmo said..
The problem is finding off the shelf fins which can handle seriously heavy weed. There are some.
The next fun part is places like Albany can absolutely destroy a leading edge within 4 hours and @ $300 a pop you just grimace a lot when you see your nice fin munted.
As the largest fin we use in these areas are generally about 23cm, 3D printing gives a good idea on fin performance without big expense as a piece of G10 to suit is +$100 just for material let alone + the days worth of machining on a CNC Router then the cleanup after.
Flex's been using PET G successfully, PC would be a better option, but more expensive and can be a pain without a heated chamber Flex has a Bamboo labs printer which I think is ok , mine (Ender 6) struggles a bit with PC.
G'day Elmo,
We use PC for 12 foot long fuselages, once you understand how to design and print with it the results are very good. ASA works great for the wings but we're using carbon spars for those to give us the strength we need, both on the fuselage and wings. We own the patent on the process. We also utilise topographical optimisation software to increase the strength of the internal structures, it's pretty amazing what we can create.
PETG on a Prusa is the easiest way to go, the time is the cad work and optimising the foil. Great if you have the bandwidth and patience to do it but I'd rather spend the time windsurfing! Mind you playing with bell curve lift distributions and Prandtl wings is fun on a long winter nights in the Gorge. Elliptical planforms are also good but work better on Spitfires (just got back from the UK after flying them at Biggin Hill).
Cheers,
Roo
Select to expand quoteRoo said..Can't wait to see the fins you print in PLA. They will be morphing fins that change shape as soon as they get sunlight on them. There's a reason we don't print aircraft with PLA! PC or ASA are a lot more stable.
You may be able to print a fin for $30 in materials but the time and effort you put into it are better spent for most people. Buying a fin for $200 will seem reasonable once you factor in your time spent designing, building and refining the process.
Gonna have to disagree with you here Roo. There are two directions we were originally going with these printed fins. The "original" intention was quick prototypes that can last one session to test out ideas before committing to more expensive, reliable methods of construction or using the better filaments. Between Fangy and my ideas I've printed at least 30 fins between us now. Often, we run a fin just one session before realising there is a better way...the concept is similar to Musk's (love or hate him) approach where build and test quickly for rapid iteration and improvement. Thus the cheaper/more environmentally friendly approach.
The other direction is of course to make long lasting, reliable fins and for sure using more exotic materials will do that. However, it appears that is not necessary as the first approach ticks this box too. The 3d printed fins using the cheap stuff anyone can print with on the cheap printers works just fine. This is especially true in the brutal Albany weed. I haven't done a real longevity test yet but so far have done about 250km in Albany on one fin and I cannot see any visible form of wear. Actually, makes life easy..don't bother sanding at all as a few hrs at Albany takes it to 1000 grit finish.
Whilst I agree I've probably spent too many hrs playing around with printed fins, I'm sure it is the same as anyone building their own gear like their own board, any artist or any other thing you can dream up. I'm sure if you count the hrs put in and all the mistakes, it's far cheaper to hand over $4k for a new board. But you'll be puking if you get the slightest scratch on it. There is a deep satisfaction of making it yourself, or, at the very least you will learn something along the way which you can apply to other stuff. Even if the thing you learn is you are not a DIY'er and happy to hand over the cash.
I also disagree that it takes a long time in CAD to design a fin. I'm rookie to this world of CAD/3D print world but I can design a new fin from scratch, print it, fill it, ready to go in under 1hr effort. (this excludes print and epoxy cure time). So even if I cost my labour at $200/hr I'm still on par with commercial fins. Not saying the fin I design is any good though. I have a video to demonstrate that, that would have been out already had it not been for sailing and testing new stuff and searching for a lost Gopro today recording tests of the new creations. I can agree that I prefer to be out sailing or building stuff than editing videos though. (however I am addicted to watching YouTube vids of people building stuff so feel obliged to reciprocate)
Select to expand quote
G'day Elmo,
We use PC for 12 foot long fuselages, once you understand how to design and print with it the results are very good. ASA works great for the wings but we're using carbon spars for those to give us the strength we need, both on the fuselage and wings. We own the patent on the process. We also utilise topographical optimisation software to increase the strength of the internal structures, it's pretty amazing what we can create.
PETG on a Prusa is the easiest way to go, the time is the cad work and optimising the foil. Great if you have the bandwidth and patience to do it but I'd rather spend the time windsurfing! Mind you playing with bell curve lift distributions and Prandtl wings is fun on a long winter nights in the Gorge. Elliptical planforms are also good but work better on Spitfires (just got back from the UK after flying them at Biggin Hill).
Cheers,
Roo
Ya Roo, glad you were not one of the pilots that went down in the Spitfire recently. I stubbled across Prandtl and bell curve lift distribution independently about 3 weeks ago after playing around with Canards and I gotta say my whole approach to everything changed overnight. (only realised last week you Braniacs have been discussing this over in the flappy leech thread for some time and elsewhere) Whilst the Canards seemed to give good improvements, its obviously not practical for most but most importantly birds don't have them so there is obviously a better way.
So I discovered Prandtl and the printer has been running flat strap, 3 failures, 1 reject and 2 successfully printed and sailed Prandtl V1 and V2 fins with over 100km sailed in range of conditions from mild to nutcase. I've been trying to disguise the fin by calling it a warp fin. The V3 fin parts hopefully arrive next week. Have tested myself (rookie intermediate sailor) and twice now with very experienced sailor. So far feedback on fin is very positive.
Gonna be really interested in what you, Chris249, IanK...and Fangman (seem to be the ones clued in here) think of the new fin and will really appreciate any feedback good or bad.
So much editing to get it out (arg!)
Unrelated: I love the Biggin, but for a different reason.....
Select to expand quoteRoo said..elmo said..
The problem is finding off the shelf fins which can handle seriously heavy weed. There are some.
The next fun part is places like Albany can absolutely destroy a leading edge within 4 hours and @ $300 a pop you just grimace a lot when you see your nice fin munted.
As the largest fin we use in these areas are generally about 23cm, 3D printing gives a good idea on fin performance without big expense as a piece of G10 to suit is +$100 just for material let alone + the days worth of machining on a CNC Router then the cleanup after.
Flex's been using PET G successfully, PC would be a better option, but more expensive and can be a pain without a heated chamber Flex has a Bamboo labs printer which I think is ok , mine (Ender 6) struggles a bit with PC.
G'day Elmo,
We use PC for 12 foot long fuselages, once you understand how to design and print with it the results are very good. ASA works great for the wings but we're using carbon spars for those to give us the strength we need, both on the fuselage and wings. We own the patent on the process. We also utilise topographical optimisation software to increase the strength of the internal structures, it's pretty amazing what we can create.
PETG on a Prusa is the easiest way to go, the time is the cad work and optimising the foil. Great if you have the bandwidth and patience to do it but I'd rather spend the time windsurfing! Mind you playing with bell curve lift distributions and Prandtl wings is fun on a long winter nights in the Gorge. Elliptical planforms are also good but work better on Spitfires (just got back from the UK after flying them at Biggin Hill).
Cheers,
Roo
Off topic but any links you'd like to share publicly on this, fuselages, wings, etc? It sounds absolutely fascinating. (As does the main topic)
Select to expand quoteFlex2 said..
G'day Elmo,
We use PC for 12 foot long fuselages, once you understand how to design and print with it the results are very good. ASA works great for the wings but we're using carbon spars for those to give us the strength we need, both on the fuselage and wings. We own the patent on the process. We also utilise topographical optimisation software to increase the strength of the internal structures, it's pretty amazing what we can create.
PETG on a Prusa is the easiest way to go, the time is the cad work and optimising the foil. Great if you have the bandwidth and patience to do it but I'd rather spend the time windsurfing! Mind you playing with bell curve lift distributions and Prandtl wings is fun on a long winter nights in the Gorge. Elliptical planforms are also good but work better on Spitfires (just got back from the UK after flying them at Biggin Hill).
Cheers,
Roo
Ya Roo, glad you were not one of the pilots that went down in the Spitfire recently. I stubbled across Prandtl and bell curve lift distribution independently about 3 weeks ago after playing around with Canards and I gotta say my whole approach to everything changed overnight. (only realised last week you Braniacs have been discussing this over in the flappy leech thread for some time and elsewhere) Whilst the Canards seemed to give good improvements, its obviously not practical for most but most importantly birds don't have them so there is obviously a better way.
So I discovered Prandtl and the printer has been running flat strap, 3 failures, 1 reject and 2 successfully printed and sailed Prandtl V1 and V2 fins with over 100km sailed in range of conditions from mild to nutcase. I've been trying to disguise the fin by calling it a warp fin. The V3 fin parts hopefully arrive next week. Have tested myself (rookie intermediate sailor) and twice now with very experienced sailor. So far feedback on fin is very positive.
Gonna be really interested in what you, Chris249, IanK...and Fangman (seem to be the ones clued in here) think of the new fin and will really appreciate any feedback good or bad.
So much editing to get it out (arg!)
Unrelated: I love the Biggin, but for a different reason.....
Flex we were over there when the Spitfire went down. Engine failure and lack of height as well as the pilot trying to avoid crashing into homes led to his demise unfortunately. The plane will be rebuilt.
Now you are into the Prandtl magic have a look at what the Horten brothers were doing in the 1940. The didn't need the long swept spans but used a shorter span long chord design. Perfect for a weed fin. Only one plane still exists, its on display at the Udvar Hazy Air and Space Museum at Dulles airport, we visit it quite often when we are in DC.
Ooh Roo! We are all over that already...even got the Horten 3d Prints for the RC model. 
. The Horten really is a beautiful bit of kit, especially given its age.
Select to expand quotefangman said..
Ooh Roo! We are all over that already...even got the Horten 3d Prints for the RC model. . The Horten really is a beautiful bit of kit, especially given its age.
I assume you have the ones from Eclipse they released recently. Wings aren't quite right, they took a few liberties so it could be 3D printed.
Did you know they built a brand new replica and tested it for the radar signature and stealth abilities at China Lake. Very interesting results.
Roo, ya by remarkable coincidence or clever design Fangman has designed his Fangy fins to closely follow the profile of the Horton bro's Ho 229...he just hasn't put the Prandtl stuff in....so I did. Picture of V1 and V2 Prandtl prototypes on right and $13 fin on left all of which have performed really well over the last 2 weeks of testing. Of course, V3 and V4 already in progress based on these successes.
I would have to question how relevant bell shaped lift distribution is to a symmetrical shallow water weed fin.
Speaking for myself only, with the cast aluminium fins way back when, I was only interested in Prandtl's work in reducing the tip vortex efficiently. In turn, I hoped this would not only lessen the drag, but also lessen the opportunity for a ventilation pathway up the vortex itself. With the recent experimental fins, I have not considered the lift curve over the entire foil in any great detail, more so just mucking about with the tip behaviour.
Once I started playing around with Flex's manufacturing method, and after studying some of his footage, I saw an opportunity for quite a bit more boffinising on fin tip flexing effects. My carbon rod layout was inspired by bat wings, as I thought that I might be able to take advantage of thousands of iterations of evolutionary pressure to do some of the experiment for me.
Having been a keen follower of NASA's reduced drag Prandtl wing stuff, I had been using Prandtl foil shapes in the tip section, but now I could really confuse things with some degree of tip flex in a fin.
Flex's manufacturing process has now given me access to multiple, rapid, cheap prototyping. This is meth for me and now causing the list of jobs given to me by the Minister of Household Affairs to blow out to several pages. I would add, however, that I do not find the tips are at all durable. In my hands, they get introduced to Mother Earth far too often!
The Prandlt bell shaped lift distribution wing uses twist....but once you use twist on a fin it becomes asymmetrical.....so how can you do it on a symmetrical fin?
